Beneficiation of bauxite



2,769,542 BENEFICIATION or BAUxrrE John Congdoii' Russell, Kitwe, NorthernRhodesiajand'i James Stephen Kennedy, Stamford, Conn., assignors, to American Cyanamid, Compauy,' New York, N. Y., a corporation of Maine No Drawing." ApplicationApril 3, 1953, Serial No. 346,777

9 Claims. ci. 209 166) This invention relates to an improved method of heneficiating bauxite ere by froth flo'fati' on.

The problem of bauxite ore beneficiation has been a serious one because of the low unit value of the product and'the fact that while it is not dificult to float bauxite, the procedures employed have resulted in poor selectivity in that the concentrate contained considerable combined silica. l

ecording to the present invention, bauxite is floated away amt silica gan'gues' by means of water-dispersible sulfonated'petroleum hydrocarbons. The bauxite ore is grfoundjand deslimeld' int'ne' presence of sodium silicateg' This deisli'rjned'bauxiteore isthenjconditioned in'ian acid circuit with a petroleum: sul fonate and subjected to froth SP-3P2, and SP-312, obtain tributors, Inc.

, However, theicomnie'rcially available sulfonatedi lei rirhyd ro earbons may be divided on a solubility into two d' "not groups: one of these isjthefgroupjvarif ously known as mahogany acids, mahogany soaps; and th lik''. This"'group"is' characterizedin that its constituents are generally oil-soluble but water-dispersible. Us'iially'fbut not necssarilwthesecompounds have a deep ahogany color wheii'in solution', which gives rise to the i in h aa ?.s a .pqu d ll.

Theother group is generally, but not necessarilychar acterized by a green coloration in solution. Hence; corn-" pounds ofthis group are usually referredto as fgreen: sulfonicf acids or green soaps. More important than the color distinction, however, is the fact that the so calle'd reen compenndsmre characterized by being watersoluble.'

So ifarias thel presnt'invntion is concerned, either gioup, o'rlja mixture the'reof,'may be used!" Thefwater soluble petroleum sulfonates appear 'to have'cei'tain nude sifable frothing properties which interfere .with selectivity. In the process of this invention, this difliculty'is readily overcome by the addition of an amount of a more hydrophobic material. This may be done by adding an oil in suitable quantity or by mixing some of the oil-soluble petroleum sulfonates With the water-soluble type;

The Watei' and'oil-solubl'e' petroleum sulfonates are 2,769,542 Patented Nov. 6, 1956 ice tiveness of theacid treatnie ntiisjnot apparently dependent" upon the nature'of the acid anion insofanas it do esnot have a particularldepfessant effect and almost any strong or fairly strong acid maybe used, eitherinorganic or organic. The limit of effectiveness appears to-lie with; acids having an ionization constant of about '10 to 7.

Sulfuric acid gives excellent iresults and because of its. extremely low cost is the preferred acid.

The mechanics whereby the presence'of an acid with petroleum sulfonates" affects the surface of the particles: hasnot as yet been fully determined and the present 'in vention is not intended to be limited to anyparticular theory of action. It is important to note that a practical advantage of the present invention lies in the fact that alhough an acid circuit is required, the pH of the circuit. is not critical providing the 'acid' used is strong-enough} Water-soluble petroleum sulfo nates and acid alone do not appearto give optimumresults, and we have found: that conditioningin thepres'ence "of an'oil is desirable 20 forbest recoveriesand grades." It is an advantage of the usedunde'r definite conditions and the present invention present invention that the nature :of the oil is not 'particul arly critical Excellent results are obtained with various hydrocarbon products such as various grades ofifuel oil and even crudeoil; Since these'oils' are'among the cheapest' commercially available"materials, they may be con sidered as the'preferred'oils 'to beused in the process of the present invention.

Conditioning andflot'ati'on procedure is not "materially" changed by the"'p resent invention, which is a further ractiearadvantage; 'as noieiiioperating techniques need tobe reamed; V The ere'may be'conditioned either at high or low solids, and well-known conditioning equipment may therefore be used, Special apparatus is unnecessary, except to the extent that the conditioning apparatus should be resistant to corrosion In common with almost all froth flotation operations on non-sulfide ores slimes are a detriment. In the process of the presen t invention, the desliming operation may be economically efiected by treating the slime-containing ore with sodium silicate or other commonly used slime-dis persing agents such as sodium hydroxide, tetrasodit'nnv pyrosphosphate, lignin sulfonates and the like, and wash-- ing until the removal of slimes is essentially complete.

It is an important advantage of the process of the present invention that it isapplicabIe to practically all the: ordinarily-occurringbauxite 'or'e's and is not restrictedto: cei't'ain particular ores. As -in the-case of most froth flotation operations, however, results will di'fir with differnt ores'.'-' lt is 'an adv'antagethat concentrations-of usable grade may beproduced from low g'rade'or'ehavinga a combined silicate content of the order of 12 or 13%.. It'is also an 'advantage'that the processis so-highly selective that in manycases concentrates of certain grade are: obtained in' an'ou'gher'operation; However, with many ores,and particularly with low-grade ores, cleaning and even 're-cleaning 'of the" rougher concentrate is advantageous. In common with f r ot li fitaierexpefiefizeifi other ores,'the"pieciseflowsheet for'be'st results winwary .somewhat from ore'to ore, and should be in accordance with best ore-dressin'g practice. The lack of criticalne ss of the present process, however, makes the choipe of plant and procedure simple and no operating difficulties are encountered.

The flotation may be conducted at the usual pulp densities, i; e'. ,'from l030% solids and may becar' ied out in anysuitable 'flotation machine. Wherehigh outputs are required, we have found that the use of highly developed flotation machines of the mechanical type, such as Fagergren flotation-machines, are desirable, but the invention is not limited thereto.

Anotheradvantage ofthe-present' invention lies' inthe fact that the flotation concentrate may be tabled to separate the heavy materials, for example, iron and titanium oxides, from the bauxite. While this additional tabling step is not necessary to the eificient operation of our process, it does result in separating the heavy materials and gives a bauxite product of very high alur'nina content. In the case of some bauxite ores,'it is of considerable commercial importance that the table concentrate contains'ilmenite, zircon and 'columbium in appreciable amounts. To our knowledge, a columbium concentrate has never been obtained from bauxite ore by the fletation and tabling processes of this invention.

The'invention will be described in greater detail in conjunction with the following specific examples. In the examples, all flotations are effected in Fagergren flotation machines operating at normal speeds and with normal air intake. V i

' Example 1 A bauxite ore analyzing 53.93% A1203, 0.98% F6203, 4.03% TiO2, 14.04% SiOz and. having a loss on ignition of 26.99%, was ground to +35 mesh, treated with 4 lbs/ton NazSiOe and deslimed. The deslimed and washed ore was then conditioned for 2 minutes at 60% solids with 6.0 lbs./ ton of a water-soluble petroleum sulfonate, 6 lbs. per ton fuel oil and 2 lbs/ton sulfuric acid. The conditioned ore was diluted to 14% solids with water and floated for 2 /2 minutes. The pH during flotation was about 3.1. The cleaned and recleaned flotation concentrate had the following analyses:

Assays Percent Product Weight Percent Percent Percent Percent Loss on 203 8203 TiOa SiO: Ignition Calculated Head. 100. 52. 42 1. 00 V 4. 00 16. 45 26. 12 Cleaned Concent.-. 76. 9 58. 61 l. 16 4. 92 5. 50 29. 81 Cleaner Tailinga. 9. 5 41. 89 0. 35 1. 5O 37. 38 18. 98 Rougher Tailing 13. 6 24. 79 0. 56 0.58 63. 76 10.31

Distribution, Percent Calculated IElIead. 100. 0 100. 0 100. 0 100. 0 100. 0 Cleaned Concentrate. 86.0 89.1 94.5 25.7 87.7 Cleaner Tailings 7. 6 3.3 3. 5 21. 6 6. 9 Rougher Tailing 6. 4 7. 6 2.0 52. 7 5. 4

Example 2 The ore of Example 1 was processed in a similar manner, except that 5 lbs/ton oil-soluble petroleum sulfonate was substituted for the fuel oil and water-soluble petroleum snlfonate. The cleaned and recleaned flotation concentrate had the following analyses;

Assays Percent Product Weight Percent Percent Percent Percent Loss on A1203 F9103 T102 SiO Ignition Calculated Head- 100. 0 52. 29 1. 17 4. 53 17. 17 24.82

Cleaned Concentrate 58. 9 59. 55 1. 60 6. 43 3. 48 28. 93 Cleaner Tai1ings-. 7. 9 51. 99 0. 58 2. 76 19. 30 25. 37 Rougher Tailing-.-- 33. 2 39. 5O 0. 55 1. 58 '40. 97 17. 40

Distribution, Percent Calculated Head 100.0 100. 0 100. 0 100. 0 100. 0 Cleaned Concentrate 67. 1 80.5 83.6 11.9 68. 6 Cleaner 'Iailings. 7. 8 3. 9 4. 8 8. 9 8. 1 Rougher Tailing 25. 1 15. 6 11.6 79. 2 23. 3

Example 3 A bauxite ore analyzing 52.07% A1203, 4.06% F403, 4.40% TiO2, 0.67% ZrOz, 12.96% S102 and having a 4 1 loss on ignition of 25.84% was ground to +35 mesh, treated with 4 lbs/ton NazSiOs and deslimed.. The de-. slimed ore was washed with water containing 1 lb./ton

NazSiOe and then conditioned for 2 minutes at 60% solids.

with 6 lbs./ ton water-soluble petroleum sulfonate, 6 lbs./

ton fuel oil and 2 lbs./ton sulfuric acid. The conditioned ore was diluted to 12.2% solids and floated for 2 minutes. The pH during flotation was about 3.1. V The flotation concentrate was separated into a heavy minerals concentrate and an alumina tailing on a Wilfley table. The separated products had the following analyses:

Assays Per- Product cent Per-' .Per- Per- Per- Per- Per- Weignt cent cent cent cent cent cent A1203 F9203 T105 ZIO: S103 LOSS on Ign.

Calculated Head 100. 0 49. 48 5. 19 5. 16 l. 04 14. 29 24. 82 Flotation C0nct 73.0 53. 02 6.00 6. 41 1. 26 6. 41 26. 87 Table Concen- V trate 11. 3 28. 86 22. 31 23. 05 5. 93 7. 12. 30 Table Tailing. 61. 7 57. 43 3.03 3.39 0.41 6. 21 29. 53 Flotn. Clnr. Tlgs- 13.6 50. 27 4. 22 2. 63 0.77 16. 74 25. 37' Flotn. Rghi. Tl". 1 3. 4 29. 47 1. 72 0.79 0.13 54. 71 13.18

Distribution, Percent Calculated Head 100. 0 100. 0 100. 0 100. 0 .100. 0 100. Flotation Concentrate--- 78. 2 84. 5 91.0 88.3 32.8 79. Table Concentrate 6. 6 48.5 50.5 64.1 6. 0 5. Table Tailing 71. 6 36. 0 40. 5 24. 2 26. 8 73. Flotatn Cleaner Tlgs- 13. 8 11. 1 6. 9 10. 0 15. 9 13. Flotatn Rougher Tlg 8. 0 4. 4 2. 1 1. 7 51.3 7.

. Example 4 A bauxite ore analyzing, 58.07% A1203, 1.32% FezOa,

3.41% TiO2, 6.8% SiO2 and having a loss on ignition of 30.37% was ground .to +35 mesh, treated with 8 lbs/ton sodium silicate and deslimed. The deslimed ore was washed with water containing 4 lbs./ton sodium silicate and then conditioned for 2 minutes at solids with 8 lbs./ton water-soluble petroleum sulfonate, 6 lbs./ ton fuel oil and 2 lbs./t0n sulfuric acid. The conditioned ore was reducedto 15.2% solids and floated for 2 minutes. The pH during flotation was about 4.' The flotation concentrate was separated into a heavy minerals concentrate and an alumina tailingon a Wilfley table; the separated products had the following analyses:

Assays Percent Product Weight Percent Percent Percent Percent Loss on A1203 F9203 T S102 Ignition Calculated Head.-- 100. 0 58. 62 1. 27 3. 38 5. 96 r 30. 76 Flotatn Concentr 46. 8 60. 15 l. 25 3. 53 2. 92 32. 13 Table Concentrate- 0. 9 52. 15 7. 66 7. 25 5. 51 27. 43 Table 'Iailing r 45.9 60.32 1. 12 3. 46 2. 87 32. 23 Flotn Clnr. 'Ilgs--- 10.6 58. 68 1.01 3. 45 6. 03 30. 83 Flotn Rougher Tlg. 42. 6 56. 91 1. 36 3. 19 9. 30 29. 24

Distribution, Percent Calculated Head; 100. 0 100. 0 100. 0 100. 0 100. 0 Flotation Concentrate.. 48.0 45. 9' 49. 0 22. 9 48. 9 Table Concentrate.-. 0. 8 5. 4 2. 0 0. 8 10. 8 Table Tailing 47. 2 40. 5 47. 0 22. 1 48. 1 Flotn Cleaner Tailings. 10. 6 8. 4 10. 8 10. 7 10. 6 Flotn Rougher Tailing- 41. 4 45. 7 40. 2 66. 4 40. 5

Example 5 A bauxite ore analyzing 52.98% A1203, 4.35% FezOs, 2.87% TiO2, 12.05% S102 and having a loss on ignition of 27.79%, was ground to -35 mesh,.treated with 6 lbs./ton sodium silicate and deslimed; the deslimed ore was conditioned for two minutes at 60% solids with 6 lbs./ton of a water-soluble petroleum sulfonate, 6 lbs./ton fuel oil and 2 lbs/ton sulfuricacid. The

conditioned ore was reduced to 10% solids and for 2imiuut'es. The .pH.during flotation was.3.6.. ,The

flotation. concentrate was separatedinto a heavy. minerals,

concentrate and an alumina tailing .onaWilfley table; the separated products had the following analyses:

Assays Percent Product Weight Percent Percent Percent Percent Loss on A1203 F9203 T10: S10: Ignition Calculated Head.-. 100. 52. 42 7. 18 2. 32 8. 66 29. -52 Flotation Ooncentr; 76. 2 e 53. 10 7. 44 2. 45 6. 47 30. 51 Table Concentrate... 6. 3 19. 94 41. 10 2. 65 9. 78 26. 53 Table Tailing 69. 9 56. 11 4. 40 2. 44 6. 17 30.88 Flotatn Clnr. 'llgs. 10. 8 51. 09 6. 26 1. 96 13. 10 27. 59 Flotatn Rghl. Tlg. 13. 0 49. 40 6. 51 1. 88 17. 83 25. 28

Distribution, Percent Calculated Head; 100. 0 100. 0 100. 0 100. 0 100. 0 Flotation Concentrate. 77. 2 78. 8 80.4 56.9 78. 8 Table Concentrate- 2. 4 36. 0 7. 2 7.1 5.7 Table Tailing 74. 8 42. 8 73. 2 49. 8 73. 1 Flotation CleanerTailmgsne 10. 9. 4 9. 1 16. 3 10. l Flotation Rougher Tailing..- 12. 3 v 11. 8 v 10. 5 26. 8 11. 1

Example 6 The ore of Example 5 was processed in a similar manner, except that 5 lbs./ton of oil-soluble petroleum sulfonate was substituted for the fuel oil and water-soluble petroleum sulfonate. The cleaned and recleaned concentrate was passed over a laboratory Wilfley table to separate the heavy minerals; the separated products had the following analyses:

Assays Percent Product Weight Percent Percent Percent Percent Loss on A1203 F8203 T103 5102 Ignition Calculated Head-.- 100. 0 52. 32 7. 53 2. 30 8. 32 29. 51 Flotation Concentr- 52. 3 54. 07 7. 88 2. 52 4. 45 31. 06 Table Concentrate" 7. 1 30. 85 31. 80 3. 57 5. 63 28.15 Table Tailing 45. 2 57. 73 4. 12 2. 36 4. 27 31. 52 Flotn Cleaner Tl S. 16. 3 51. 39 8. 55 2. 05 8. 57 29. 44 Flotn Rougher T g. 31. 4 49. 87 6. 44 2. 07 14. 63 26. 99

Distribution, Percent Calculated Head 100. O 100. 0 100. 0 100. 0 100. 0 Flotation Concentrate 54. 1 54. 7 57. 3 28. 0 55.1 Table Concentrate-. 4. 2 30.0 11. 0 4 8 6.8 Table Tailing 49. 9 24. 7 46. 3 23. 2 48. 3 Flotation Cleaner Ta1l1ngs 16. 0 18. 5 14. 5 16. 8 16. 2 Flotation Rougher Tailing 29. 9 26. 8 28. 2 55. 2 28.7

Example 7 A bauxite ore analyzing 52.83% A1203, 2.54% F6203, 2.78% TiOz, 16.01% S102 and having a loss on ignition of 25.82%, was ground to +35 mesh, treated with 7 1bs./ton sodium silicate and deslimed; the deslimed ore was conditioned for 2 minutes at 60% solids with 6 lbs/ton water-soluble petroleum sulfonate, 6 lbs/ton fuel oil, and 2 lbs./ton sulfuric acid. The conditioned ore was reduced to 11.3% solids with water and floated for 2 minutes. The pH during flotation was about 3.6. The cleaned and recleaned flotation concentrate was passed over a laboratory Wilfley table to separate the heayy rninerals. The separated products had "the'follEiwing analyses:

. Percent Product Weight a Percent Percent Percent Percent Loss on 13.1203 F9203 T103 S10: gm'tion Calculated Head 100. 0 56. 01 2. 61 2. 61 9. 87 Flotation Concen- A I trate 69. 3 57.33 2. 59, 2. 78 7. 13 Table Concentrate" 1. 4 35. 76 23. 45 13. 98 6. 35 Table Failing 67. 9 57. 77 2.17 2. 55 7. 15 Flotation Cleaner Y Tailings 14. 5 54. 10 2. 50 2. 43 13. 87 Flotation Rougher 1 Tailing 16.2 52.10 2 71 acs 18.01

p 7 DistributiomPercent Calculated Head 100.0 100.0 100.0 100.0 100.0 Flotation Concentrate- 70.9 68.9 73.9 50.1- 72.3 Table Concentrate. i 0.9 12.5 7. 5; 0.9 4 1.0 Table Tailing 70.0 I 56.4 66. 4 49.2 71.3 Flotation Cleaner Tailings 14. 0 13.9 13.5 20. 4 l3. 6 Flotation Rougher Tailing 15.1 17.2 12.6 29.5 14.1

Example 8 The ore of Example 7 was processed in a manner similar to that described in Example 7, except that 5 lbs./ton of oil-soluble petroleum sulfonate was substituted for the fuel oil and water-soluble petroleum sulfonate. The cleaned and recleaned flotation concentrate was passed over a Wilfley table. The separated products had the following analyses:

Assays Percent Product Weight Percent Percent Percent Percent Loss on A1 03 F920 TiOz S10; Ignition Calculated Head 100. 0 56. 36 2. 59 2. 63 9. 60 28. 80 Floation Concept- 51. 5 58. 77 2. 66 2.81 4. 97 30. 78 Table Concentrate 1. 2 44. 24 16. 44 12. 10 4. 37 22. Table Tailing- 49. 9 59. 13 2. 32 2. 58 4. 99 30. 98 Flotn Clnr. T b 15.8 55. 68 2. 70 2. 59 10. 38 28.65 Flot'n Rghr. Tlg- 33. 1 52. 2. 46 2. 39 16. 37 25. 83

Distribution, Percent Calculated Head" 100. 0 100. 0 100. 0 100. 0 100. 0 Flotation Concent 53. 3 52. 2 54. 4 26. 5 54. 6 Table Concentrate 0. 9 7. 6 5. 5 0.6 0. 9 Table Tailing- 52. 4 44. 6 48. 9 25. 9 53. 7 Flotation Cleane D 15. 6 16. 4 15. 5 17. 1 15. 7 Flotation Rougher Tailing. 31. 1 31. 4 30. 1 56. 4 29.7

Example 9 Example 1 was repeated but the deslimed ore was conditioned at 30% solids instead of at 60% solids. The cleaned and recleaned flotation concentrate had the following analyses:

Assays Percent Product Weight Percent Percent Percent Percent Loss on A1 0 FezO; T102 5101 Ignition Calculated Head 100. 0 48. 87 0. 78 4. 05 16. 17 24. 02 Flotation Concent.. 86. 7 56. 39 0.90 4. 97 9. 59 28.15 Flotatn Clnr. Tlgs 4. 3 32. 95 0.30 0. 36 53.16 13. 23 Flotatn Rghr. Tlg. 9. 0 22. 24 0.50 0.31 68. 45 8. 59

Distribution, Percent Calculated Head 100. 0 100. 0 100. 0 100. 0 100. 0 Flotation Concentrate 93. 0 92.6 98. 9 47. 8 94. 4 Flotation Cleaner Tailmgs 2. 9 1. 6 0.4 14.1 2. 4 Flotation Rougher Tailing. 4. 1 5. 8 0.7 38.1 3. 2

We claim:

which comprises conditioning in an acid circuit with a petroleum sulfonate a deslimed ore ground to about 35 mesh; and floating to recover a flotation concentrate rich in A1203 and low in silica.

' 2.'A methodaccording to claim 1 in which said petroleum sulfonate is an oil-soluble petroleum sulfonate.

, 3. A method according to claim 1 in which said petroleum sulfonate is a mixture of oil-soluble and watersoluble petroleum sulfonates.

4. A method of beneficiating bauxite-containing ores which comprises conditioning in an acid circuit with a water-soluble petroleum sulfonate and fuel oil a deslimed ore ground to about 35 mesh; and floating to recover a flotation concentrate rich in A1202 and low in silica. 5; A method according to'claim 1 in which the beneficiated flotation concentrate is passed over a table to give a heavy mineral fractior'i'and a light mineral fraction rich in A1203. V

6. A method according to claim 1 in which the beneficiated flotation concentrate is passed over a table to give a heavy mineral fraction containing colurnbium and a light mineral fraction rich in A1203. 7

7. A method according to claim 2 in which the bene ficiated flotation concentrate is passed over a table to give a heavy mineral fraction and a light mineral fraction rich in A1202.

8 A method according to claim 3 in 'which the benegive a heavy mineral fraction and a light mineral frac- 10 tion rich in A1203. 7 i

References Cited in the file of patent UNITED STATES PATENTS 2,442,455 Booth et al. June 1, 1948 2,483,192

Gieseke V 7 7 Sept. 27; 1949 FOREIGN PATENTS OTHER REFERENCES 7 U. S. Bureau'of Mines Report of Investigations R. I.

- (Copy in Scientific Library.)

Booth Dec. 23, 1947 

1. A METHOD OF BENEFICIATING BAUXITE-CONTAINING ORES WHICH COMPRISES CONDITIONING IN AN CIRCUIT WITH A PETROLEUM SULFONATE A DESLIMED ORE GROUND TO ABOUT 35 MESH; AND FLOATING TO RECOVER A FLOTATION CONCENTRATE RICH IN AL2O3 AND LOW IN SILICA. 